1. Technical Field
The present disclosure relates to a carrier leakage correction device and a carrier leakage correction method, which correct carrier leakage caused in a transmission modulation wave in a quadrature modulator.
2. Description of the Related Art
Standardization of IEEE802.11ad of the Institute of Electrical and Electronics Engineers (IEEE) as a communication standard for wireless local area networks (LANs) has been promoted in recent years. For example, IEEE802.11ad employs phase modulation, quadrature amplitude modulation, or orthogonal frequency division multiplexing (OFDM) as a modulation scheme for data transmission. Since such a modulation scheme is employed, a quadrature modulator is used so as to convert a baseband signal into a modulation signal of a microwave or a millimeter wave.
While the quadrature modulation is desirably performed in, for example, a band of a millimeter wave so as to inhibit increase in circuit scale, the millimeter wave has a high frequency and crosstalk of the high-frequency signal easily occurs inside the circuit of a transmission device, which is for example, a quadrature modulator, and carrier leakage easily occurs in the high-frequency signal after the quadrature modulation. The carrier leakage is an undesired component for the reception in a reception device and decreases the detection accuracy of a reception signal. Thus, when the transmission device generates a high-frequency signal, it is needed to suppress carrier leakage caused in the high-frequency signal in a quadrature modulator.
For example, U.S. Pat. No. 8,078,123 discusses a technique for suppressing carrier leakage caused in a high-frequency signal in a quadrature modulator. U.S. Pat. No. 8,078,123 discloses that a signal is supplied to the quadrature modulator and envelope detection is performed on the output of the quadrature modulator to obtain an amplitude, and an offset correction value input to the quadrature modulator so as to decrease a fluctuation amount of the amplitude is adjusted to suppress the carrier leakage.